Pressure-applying device for two or more concentric transformer windings



Sept. 2, 1930. G. AMMANN El AL 1,775,015

} PRESSURE APPLYING DEVICE FOR TWO OR MORE CONCENTRIC TRANSFORMER WINDINGS Filed Mag 14. 1928- Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE GEORG AMMANN, OF NEUENHOF, AND JOI-IANNES KIIBLER, OF :MANNSBERGWEG, BADEN, SWITZERLAND, ASSIGNORS TO AKTIENGESELLSGHAFT: BROWN, BOVER-I AND (3113., OF BADEN, SWITZERLAND PRESSURE-APPLYING DEVICE FOR TWO OR MOB-E CONCENTRIC TRANSFORMER WINDINGS Application filed May 14, 1928, Serial No. 277,723, and in Germany May 23, 1927.

Pressure applying devices for two or more concentric transformer windings have already been proposed in which a compression spring common to several windings produces the requisite pressing pressure by means of a force transmitting member journalled in spherical depressions. Among other drawbacks the known means have the particular disadvantage that owing to the change in the dimensions in the height direction of the windings, due to the windings settling, an unfavourable distribution of the pressing forces results, which may be so great that one of the windings will be entirely relieved from pressure. The reason for this is that with the inclined position of the force transmitting member the point of application of the pressure applying force is displaced laterally out of its normal position.

According to the present invention this disadvantage is overcome by the point of application of the pressure applying force of the pressure spring on the pressure applying member or the centre of rotation or the axis of rotation of'the latter being displaced to such an extent that it lies approximately in a straight line or in one plane with the point of support of the same on the ends of the windings.

In the accompanying drawing several constructional examples of pressing devices for windings according to the present invention are illustrated. Figs. 1 and 2 show in longitudinal section and plan view respectively a pressing device for two concentric windings, Figs. 3 and 4;, also in longitudinal section and plan view, such a device for three windings and Fig. 5 a constructional modification.

In all the figures a a are the concentric transformer windings, and 6 the pressure applying rings located above the same. 0 is a spindle fixed rigidly to the transformer body, which spindle is provided with an adjustable nut g which acts as an abutment for the pressure applying spring d. On the spindle 0 the pressure piece 7 is guided, which may coact with the guiding end of the spindle to form an oil buffer. The force transmitting member between the pressure piece f and the supporting pins 6 of the pressure rings 6 b bears the reference letter In In the constructional examples shown the force transmitting member h has a three point support on the winding ends.

ing force on the force transmitting member is selected in accordance with the pressing pressures to be exerted on the windings. The force transmitting member it according to Figs, 1 to 3 is provided with spherical depressious, in which the spherical supporting pins 6 and the spherical end of the pressure piece f engage. In the arrangement shown in Fig. 5 the converse arrangement is adopted, namely the spherical depressions are provided in the supporting pins and inthe pressure piece, while the-force transmitting member has corresponding spherical bearing members. The arrangement may also be such that the force transmitting member has both spherical depressions and spherical bearing members.

The displacement of the. pointof application of the pressing force or the centre point of the spherical member or spherical depression for the engagement of the compression sp ing on the force transmitting member in a straightline or aplane with the points of support of the latter on the windings, as shown in the drawing, has the advantage that the distribution of the force and the direction of the pressing force exerted by the compression spring remain unaltered, even when the force transmitting member cants. Hence there is no change in the distribution of force of the pressing pressure acting on the windings, even if one of the windingsshould settle, the motion of the force transmitting member with reference to the points of support,

This three point support has proved, to be particularly suitable forgenabling, in

due to a canting of the said member, being reduced to a minimum.

The pressing device according to the invention has the further advantage that the concentric windings more particularly their pressure applying rings are guided as regards their positions relative to one another, so that no displacements of the windings relative to one another can take place. In place of some of the spherical surfaces, such as those described with reference to the con structional examples for acting as bearings for the force transmitting member between the winding ends and the pressure piece, knife edges may be used.

lVhat we claim is:

1. A pressure device for a plurality of concentric transformer windings including a hemispherical ended member a compression spring bearing upon said member an intermediate member and a hemispherical ended member on the end of each of said concentric windings, the said parts being so arranged that the centre of the hemispherical end of the first-named member lies approximately in a tangential plane. common to the hemispherical ends of the members which rest on the ends of said'concentric windings.

2. A pressure device as claimed in claim 1 wherein the said intermediate member contacts with the members resting on the ends of the windings in three points.

3. A pressure device as claimed in claim 1 wherein the said intermediatemember con tacts wth the members resting onthe ends of the windings in three points two of which are on that winding to which the greatest load has to be applied.

4. A pressure device as claimed in claim 1 wherein the said intermediate member contacts with the members resting on the ends ofthe windings in three points one on each of three windings. r

5. A pressure device as claimed in claim 1 wherein the said intermediate member contacts with the members resting on the ends of the windings in three points and the bearing between the intermediate member and the members resting upon the windings is so constructed that the winding ends cannot be displaced laterally with respect to one another. i

In testimony whereof we have-signed our names to this specification.

' GEORG AMMANN.

JOHANNES KUBLER. 

